Questions on using this Site - Please Help

I see no real Help anywhere on this site, other than one Instructable on How to create Instructables - but it was all ettiquette and fomr tips. Even the "Help" link takes you to a "Guided Tour" that tells you very little. These things should be explained to all who join. Please tell me the answers - and thanks !!
- how can I delete files from my Library - initially I uploaded 3 meaningless test pics and I see no option to delete
- how the "Tags" work and what they are for
- I see an option to "View by Tags" or "View by Filetype" - why should I view by filetype?
- do you "have to use Tags" to refer to your files - or can you use the filenames instead
- how to post up multiple instructables, where you may end up with over 100 image files - and separate the files for each in a logical manner (i.e. can you have more than one Library per user, can you make Folders in your Library, etc)
- what is the max limits on an Instructbale: i.e. number of pics
limit, size of pics limit, kByte total limit
- how to link in files from your site if possible
- how to use the "Link" and "Video" buttons in the messages without them popping up to the top of your message
- this is the only site that I frequent that is very very slow - especially when I click a page with a buncvh of comments - I have to wait quite a while before I can scroll down. Anyone else have this problem? I have great speed on virtually every other site I visit - but this one is alway slow.
The inner-workings of this are not cleat or obvious to me, and I certainly have been working with websites and forums for a lot of years. Even 1 page of directions would be greatly appreciated.

Did you make this instructable?

I made some changes to video handling in Firefox.Playing videos was choppy until I changed everything over to different player.I didn't change anything other than videos to the player.As far as I know, no Javascript things were changed, other than for video.But since I changed the settings I can't change between pictures on a step.What do you think I did?What happens when I click pictures?What is the process?To help I installed Firebug.I'm going to check out the tutorial on Firebug, so no info from it now...

I've also noticed there's an issue with swapping images in the same step. I've had success with saving my work, moving to another step, then coming back and trying again. Alternatively you can remove the image and force a reorder that way.

I restored all the video handling settings to their defaults.Result?No change I still can't click on the next picture below the first picture on the step.The frame turns orange but nothing happens when I click it.Help?!

You need to first have the video uploaded and running on some other site like Youtube( you have to set up an account there). Grab the embed code(you must select the "use old code" button on youtube for compatibility) and insert that on the video link(filmstrip button) when you go back in to edit your instructable. Good luck.